Diseases which affect human beings may be categorized according to the mechanism of their cause. For example, diseases that have an immunological component or etiology include infectious diseases, acute and chronic inflammatory diseases, cancer, transplantation and autoimmune diseases.
Examples of autoimmune diseases include multiple sclerosis (MS), autoimmune uveitis, autoimmune uveoretinitis, autoimmune thyroiditis, Hashimoto's disease, insulitis, Sjogren's syndrome, spontaneous abortions, experimental autoimmune myocarditis, rheumatoid arthritis (RA), inflammatory bowel disease (IBD), Crohn's disease, lupus (SLE), psoriasis and diabetes, particularly type I.
Additional examples of autoimmune diseases include Acute necrotizing hemorrhagic leukoencephalitis, Addison's disease, Agammaglobulinemia, Allergic asthma, Allergic rhinitis, Alopecia areata, Amyloidosis, Ankylosing spondylitis, Anti-GBM/Anti-TBM nephritis, Antiphospholipid syndrome (APS), Autoimmune aplastic anemia, Autoimmune dysautonomia, Autoimmune hepatitis, Autoimmune hyperlipidemia, Autoimmune immunodeficiency, Autoimmune inner ear disease (AIED), Autoimmune myocarditis, Autoimmune thrombocytopenic purpura (ATP), Axonal & neuronal neuropathies, Bal's disease, Behnet's disease, Bullous pemphigoid, Cardiomyopathy, Castleman disease, Celiac sprue (nontropical), Chagas' disease, Chronic fatigue syndrome, Chronic inflammatory demyelinating polyneuropathy (CIDP), Churg-Strauss syndrome, Cicatricial pemphigoid/benign mucosal pemphigoid, Cogan's syndrome, Cold agglutinin disease, Congenital heart block, Coxsackie myocarditis, CREST disease, Essential mixed cryoglobulinemia, Demyelinating neuropathies, Dermatomyositis, Devic disease, Discoid lupus, Dressler's syndrome, Endometriosis, Eosinophilic fasciitis, Erythema nodosum, Experimental allergic encephalomyelitis, Evan's syndrome, Fibromyalgia, Fibrosing alveolitis, Giant cell arteritis (temporal arteritis), Goodpasture's syndrome, Graves' disease, Guillain-Barr syndrome, Hemolytic anemia, Henoch-Schonlein purpura, Herpes gestationis, Hypogammaglobulinemia, Idiopathic thrombocytopenic purpura (ITP), IgA nephropathy, Immunoregulatory lipoproteins, Inclusion body myositis, Insulin-dependent diabetes (type 1), Interstitial cystitis, Juvenile arthritis, Juvenile diabetes, Kawasaki syndrome, Lambert-Eaton syndrome, Leukocytoclastic vasculitis, Lichen planus, Lichen sclerosus, Ligneous conjunctivitis, Linear IgA disease (LAD), Lyme disease, Meniere's disease, Microscopic polyangiitis, Mixed connective tissue disease (MCTD), Mooren's ulcer, Mucha-Habermann disease, Myasthenia gravis, Myositis, Narcolepsy, Neutropenia, Ocular cicatricial pemphigoid, Osteoarthritis, Palindromic rheumatism, Paraneoplastic cerebellar degeneration, Paroxysmal nocturnal hemoglobinuria (PNH), Parsonnage-Turner syndrome, Pars planitis (peripheral uveitis), Pemphigus, Peripheral neuropathy, Perivenous encephalomyelitis, Pernicious anemia, POEMS syndrome, Polyarteritis nodosa, Type I, II, & III autoimmune polyglandular syndromes, Polymyalgia rheumatica, Polymyositis, Postmyocardial infarction syndrome, Postpericardiotomy syndrome, Progesterone dermatitis, Primary biliary cirrhosis, Psoriatic arthritis, Idiopathic pulmonary fibrosis, Pyoderma gangrenosum, Pure red cell aplasia, Raynaud's phenomenon, Reflex sympathetic dystrophy, Reiter's syndrome, Relapsing polychondritis, Restless legs syndrome, Rheumatic fever, Sarcoidosis, Schmidt syndrome, Scleritis, Scleroderma, Sperm & testicular autoimmunity, Stiff person syndrome, Subacute bacterial endocarditis (SBE), Sympathetic ophthalmia, Takayasu's arteritis, Temporal arteritis/Giant cell arteritis, Thrombocytopenic purpura (TTP), Autoimmune thyroid disease, Tolosa-Hunt syndrome, Transverse myelitis & necrotizing myelopathy, Ulcerative colitis, Undifferentiated connective tissue disease (UCTD), Vasculitis, Vesiculobullous dermatosis, Vitiligo and Wegener's granulomatosis.
Non-limiting examples of types of cancer include adrenocortical cancer; Malignant melanoma; Non-melanoma skin cancer; Cutaneous T-cell Lymphoma; Kaposi's Sarcoma; Bladder cancer; Colon cancer; Colorectal cancer; Rectal cancer; Neuroectodermal and Pineal cancer; Childhood Brain Stem Glioma; Childhood Cerebellar Astrocytoma; Childhood Cerebral Astrocytoma; Childhood medulloblastoma; Childhood visual pathway Glioma; Meningioma; Mixed Glioma; Oligodendroglioma; Astrocytoma; Ependymoma; Pituitary adenoma; Metastasic Adenocarcinoma; Acoustic neuroma; Paravertebral Malignant teratoma; Breast cancer; Ductal carcinoma; Mammary gland neoplasia; Ovarian cancer; Carcinoid tumour; Cervical cancer; Uterus cancer; Endometrial cancer; Vaginal cancer vulva cancer Gestational Trophoblastic cancer; Fallopain cancer; Uterine sarcoma; Leukemia; Lymphoma (Hodgkin's disease and Non Hodgkin's disease); Neuroblastom; Retinoblastoma; Soft tissue Sarcomas; Wilm's tumour; Fanconi Anaemia; Langerhan's Cells Histiocytosis; Malignant Rhabdoid Tumour of Kidney; Liver cancer; Neuroblastoma; Retinoblastoma; Choriocarcinoma; Endocrine cancers; Endometrial cancer; Esophageal cancer; Ewing's Sarcoma; Eye cancer; Gastric cancer; Gastrointestinal cancers; Genitourinary cancers; Glioma; Gynaecological cancers; Head and neck cancer; Hepatocellular cancer; Hypopharynx cancer; Islet call cancer; Kidney cancer; Laryngeal cancer; Lung cancer; Lymphoma; Male breast cancer; Melanoma; Mesothelioma; Myeloma, multiple; Nasopharyngeal cancer; Non-melanoma Skin cancer; Oesophageal cancer; Osteosarcoma; Ovarian cancer; Pancreas cancer; Pituitary cancer; Prostate cancer; Renal cell carcinoma; Retinoblastoma; Rhabdomyosarcoma; Sarcoma; Skin cancer; Squamous cell carcinoma; Stomach cancer; Testicular cancerthymus cancer; Thyroid cancer; Transitional cells cancer; Trophoblastic cancer; Uterus cancer; Acute Lymphatic leukemia; Acute myeloid leukemia; Adenocystic carcinoma; Anal cancer; Bone cancer; Bowel cancer; Ductal carcinoma; Liposarcoma; Neuroblastoma; Nephroblastoma and Osteosarcoma.
Inflammatory diseases include sepsis, endotoxemia, pancreatitis, uveitis, hepatitis, peritonitis, keratitis, SIRS and injury-induced inflammation.
Diseases linked to fertility include male infertility and female infertility.
Male infertility can be caused by a variety of problems. Some of the more common disorders are listed below.                Deficient Sperm Production: Ninety percent of male infertility is caused by the failure to produce enough sperm. Azzospermia occurs when no sperm is produced while olibospermia is diagnosed when few sperm are produced. Since most sperm are destroyed before ever reaching the egg, the more sperm there are the better the chances that one will successfully fertilize the egg. However, a low sperm count, or a total sperm count of less than 5 million/ml, does not necessarily mean that a man is infertile if the sperm that he does have are healthy, properly formed, and mobile.        Varicocele: A varicose vein around one of the two spermatic cords can cause blood to pool in the testes; this, in turn, causes the temperature to increase in this area. Higher temperatures decrease sperm production and can lead to infertility. Fortunately, this problem can be fixed by surgery.        Other Disorders: Other disorders that can cause male infertility include abnormal development or damage of the testes (caused by endocrine disorders or inflammation), disorders of accessory glands, coital disorders, exposure to diethylstilbestrol (DES) a synthetic estrogen used in the 1950's and 1960's that caused cysts in the male reproductive tract, undescended testicles, and in rare cases genetic disorders such as a chromosomal abnormality.        
Female infertility can also be caused by a variety of problems. Some of the more common disorders are listed below.                Polycystic Ovarian Disease: This disease is the most common cause of ovulation disorders in women and is characterized by the presence of many minute cysts in the ovaries, by excess production of androgens, and by infrequent periods (obliomenorrhoea) or absent periods (amenorrhoea). The failure to ovulate is the most common cause of female infertility and can occur for no apparent reason or as the result of stress, hormonal imbalances, and various diseases and disorders of the reproductive system (some of which will be described below).        Pelvic Inflammatory Disease: This infection of the reproductive tract can lead to blocked or damaged fallopian tubes and is usually caused by sexually transmitted disease, miscarriages, abortions, childbirth, or an intrauterine device.        Ovulatory Dysfunction: This disorder occurs when a woman's ovaries are not producing eggs or are producing fewer eggs than usual because of age, hormonal imbalances, or other problems.        Uterine Fibroids: These benign uterine tumors occur in 40% of women and can interfere with embryo implantation or fetal growth.        Endometriosis: This disorder occurs when the tissue which lines the uterus (the endometrium) grows into growths or lesions outside of the uterus (usually on the ovaries, fallopian tubes, and ligaments that support the uterus; the area between the vagina and the rectum; the outer surface of the uterus; the lining of the pelvic cavity; the bladder, bowel, vagina, cervix, vulva, and in abdominal surgical scars). In sync with the menstrual cycle, this tissue builds up, breaks down, and sheds each month; but unfortunately, it has no way of leaving the body. As a result it causes internal bleeding, breakdown of blood and tissue from the lesions, and most often inflammation which can cause pain, infertility, scar tissue formation, adhesions, and bowel problems.        Immunological Infertility: This disorder occurs when the woman's system produces antisperm antibodies which destroy her partner's sperm.        
Disorders of carbohydrate metabolism occur in many forms. The most common disorders are acquired. Acquired or secondary derangements in carbohydrate metabolism, such as diabetic ketoacidosis, hyperosmolar coma, and hypoglycemia, all affect the central nervous system. Many forms and variants of peripheral nerve disease also are seen in diabetes. The remaining disorders of carbohydrate metabolism are the rare inborn errors of metabolism (i.e. genetic defects).
The acquired disorders of carbohydrate metabolism are fairly common, both in the United States and internationally. Hypoglycemia is a common cause of neurological disease, especially acute mental deterioration, memory loss, disorientation, obtundation, and coma, among both alcoholics and patients with diabetes who are treated with insulin. Hyperinsulinemia from other causes is rare, but pancreatic tumors could be the cause. Diabetes, with its various neurological complications, is among the most common disorders treated in adult patients. Diabetic ketoacidosis still occurs, though education and close medical follow-up make it less common than it was several decades ago. Hyperosmolar coma is also less a problem than when it was first brought to the attention of internists by Plum and Posner's classic monograph Diagnosis of Stupor and Coma. Hyperosmolar coma still occurs and needs to be kept in mind while evaluating an obtunded patient.
The inherited disorders of carbohydrate metabolism are rare. Severe defects of the pyruvate dehydrogenase (PDH) complex and the benign chemical anomaly called pentosuria have been reported in very few (2-6) patients.
Hypoglycemia, diabetic ketoacidosis, and hyperosmolar coma are all potentially fatal but potentially curable conditions.